wo viruliferous Rhopalosiphum padi(BYDV)can be detected by indirect enzyme-linkedimmunosorbent assaay(ELISA).Based on that result,a Aphid Acquisition-Enzyme-linked im-munosorbent assay(AA-ELISA)has been established for identification of barley resistance toBYDV.The OD value of AA-ELSA showed that the barley variety 877-16 carrying YD2 genewas significantly different from that of susceptible variety Manley.No significant difference wasfound between 877-16 and Manley when they were detected directly by ELISA at the same leave.